Non-return valve for a petrochemical reactor

ABSTRACT

A rapidly replaceable non-return device ( 110 ) for a petrochemical refinery reactor ( 112 ), of the type comprising: a support tube ( 114 ), connected to a portion of the reactor ( 112 ), this support tube ( 114 ) being provided internally with a cartridge ( 116 ) containing a ball ( 118 ), the cartridge ( 116 ) having, around an inlet hole ( 121 ) for a processed fluid, a seat ( 122 ) for housing the ball ( 118 ), and having slots ( 120 ) for the outflow of the said processed fluid; the cartridge ( 116 ) is fitted removably in the support tube ( 114 ).

The present invention relates to a rapidly replaceable non-return devicefor a petrochemical refinery reactor. Cylindrical devices acting asnon-return valves are used in petroleum refinery reactors in somepetrochemical processes. These devices allow the product subjected tothe refining process to flow in one direction, while preventing thebackward flow of the product and of any particles of catalyst whichwould damage the equipment located upstream of the said devices.

In the current technical language these cylindrical devices are called“risers”.

Their operation is simple: each device has a terminal part housing aball which is pushed by the pressure of the flow of the process fluidland is thus displaced axially until it uncovers radial slots throughwhich the fluid can flow out.

Any back pressure pushes the ball towards a suitable shaped housing,allowing it to form a seal and thus prevent a flow in the backwarddirection.

Clearly, the axial and radial movements of the ball cause deformation,erosion and damage to its housing which result in the wear and sometimesthe fracture of the said device, thus obliging the operator to replaceit.

At the present time, these devices are either welded or fixedmechanically inside reactors, in a vertical position. The weldingitself, as well as the formation of process residues, causes problemsfor the removal of the device, making the work slow and particularlydifficult to carry out.

In the prior art, each non-return device is made in two or more parts,namely a support tube welded to the reactor and having within it acylindrical cartridge which contains the ball and the sealing surface ofthe housing.

In fact, as described above, solid residues of the process fluidinfiltrate between the contact surfaces of the cartridge and the supporttube, thus practically bonding the two parts and making them verydifficult to disassemble: the operator is frequently obliged to replacethe whole device, with an increase in time and cost.

The object of the present invention is therefore to overcome thedrawbacks mentioned above, in particular by providing a rapidlyreplaceable non-return device for a petrochemical refinery reactor whichenables the plant downtime to be limited.

Another object of the present invention is to provide a rapidlyreplaceable non-return device for a petrochemical refinery reactor whichmakes it possible to have assured replacement times, so that plantdowntime can be correctly scheduled.

A further object of the present invention is to provide a rapidlyreplaceable non-return device for a petrochemical refinery reactor whichis particularly reliable, simple, functional and relatively inexpensive.

These and other objects of the present invention are achieved byproviding a rapidly replaceable non-return device for a petrochemicalrefinery reactor as described in claim 1.

Further characteristics of a rapidly replaceable non-return device for apetrochemical refinery reactor are specified in the subsequent claims.

The characteristics and advantages of a rapidly replaceable non-returndevice for a petrochemical refinery reactor according to the presentinvention will be made clearer by the following description, provided byway of example and without restrictive intent, with reference to theattached schematic drawings in which:

FIG. 1 is a sectional view in lateral elevation of a non-return devicefor a petrochemical refinery reactor according to the known art; and

FIG. 2 shows a sectional exploded view of a rapidly replaceablenon-return device for a petrochemical refinery reactor according to thepresent invention.

With reference to FIG. 1, this shows a non-return device, indicated as awhole by 10, for a petrochemical refinery reactor 12 according to theknown art.

The non-return device 10 comprises a support tube 14, connected to aportion of the reactor 12, within which is fitted a cylindricalcartridge 16 which contains a ball 18.

The cartridge 16 has lateral slots 20 for the outflow of the processedfluid, which also passes through corresponding apertures in the supporttube 14 in which the cartridge 16 is inserted.

The cartridge 16 also has in its lower part, around an inlet hole 21 forthe processed fluid, a seat 22 for housing the ball 18.

In the example in FIG. 1, it can be seen that the support tube 14 iswelded on to a portion of the reactor 12 in a vertical position.Alternatively, this support tube 14 can be fixed by mechanical means.

FIG. 2 shows a rapidly replaceable non-return device 110 for apetrochemical refinery reactor 112, according to the present invention,in which components identical and/or equivalent to those of the knownart shown in FIG. 1 are given the same reference numbers with theaddition of 100.

The non-return device 110 comprises a support tube 114, connected to aportion of a reactor 112, within which is provided a cylindricalcartridge 116 containing a ball 118.

The cartridge 116 has lateral slots 120 for the outflow of the processedfluid, which also passes through corresponding apertures in the supporttube 114 in which the cartridge 116 is inserted.

The cartridge 116 also has in its lower part, around an inlet hole 121for the processed fluid, a seat 122 for housing the ball 118.

In the example of FIG. 2 it can be seen that the support tube 114 iswelded on to a portion of the reactor 112, in a vertical position.Alternatively, this support tube 114 can be fixed by mechanical means.The cartridge 116 is positioned in the support tube 114 in a removableway. This is done by providing the support tube 114 with a significantdegree of deformability and elasticity in the area housing the cartridge116, or by providing particular geometrical shapes for a coupling, ofthe conical type for example, between the cartridge 116 and the supporttube 114, to facilitate the extraction of the cartridge.

The extraction can be facilitated by using suitable materials, heattreatments, machining by stock removal, or plastic treatment.

By way of example and without restrictive intent, FIG. 2 shows how atleast one longitudinal aperture 124 is formed in the support tube 114,in the area housing the cartridge 116. These longitudinal apertures 124can be, for example, milled cuts made along the axis of the support tube114. More precisely, these milled cuts are created from an upper edge ofthis support tube 114.

A taper washer 126 is also provided for fixing the cartridge 116 to thesupport tube 114.

The operation of the rapidly replaceable non-return device 110 for apetrochemical refinery reactor according to the invention is clearlyindicated by the above description provided with reference to thefigures, and is briefly as follows.

The ball 118 is pushed by the pressure of the flow of the process fluidwhich enters through the inlet hole 121, and is displaced axially untilit uncovers the slots 120 through which the fluid flows out.

Any back pressure pushes the ball 118 towards the seat 122, which issuitably shaped, enabling these components to form a seal and thuspreventing the backward flow of the processed fluid.

If the non-return device 110, and particularly the seat 122, becomesdamaged, the cartridge 116 is replaced in order to bring the device 110back into good working order.

The replacement of the cartridge 116 is made rapid and easy by theapertures 124 formed in the tube 124, which give the tube 124 anelasticity such that its upper part can be widened during the removal ofthe cartridge 116.

When the damaged cartridge 116 has been removed and replaced with a newcartridge 116, the taper washer 126 fixes the new device 110 and ensuresproper adhesion between the support tube 114 and the new cartridge 116.The characteristics of the rapidly replaceable non-return device for apetrochemical refinery reactor according to the present invention, andthe advantages thereof, are clear from the above description.

The following remarks and comments will be made in conclusion, in orderto define the aforesaid advantages more precisely and clearly.

In the first place, it should be noted that the non-return deviceaccording to the present invention does not have to be replaced as awhole, in case of damage to the cartridge, except, obviously, in case ofdamage which may occasionally occur to the support tube. The replacementtime for the non-return device is therefore reduced.

The advantage of having assured replacement times, and consequently thepossibility of correctly scheduling plant downtimes, should also beemphasized. Additionally, the use of non-return devices according to theinvention ensures that reactors will always operate with non-returndevices in optimal conditions, because of the rapidity of replacement.

Finally, it is pointed out the simplicity and reliability of use of thenon-return devices according to the invention, and the low productioncosts, with respect to the known art.

Clearly, the rapidly replaceable non-return device for a petrochemicalrefinery reactor designed as stated can be modified and varied innumerous ways within the scope of the invention; all components can alsobe replaced with technical equivalent elements. In practice, thematerials used, and their forms and dimensions, can be chosen at willaccording to technical requirements.

The scope of protection of the invention is thus delimited by theattached claims.

1. Rapidly replaceable non-return device (110) for a petrochemicalrefinery reactor (112), of the type comprising a support tube (114),connected to a portion of the said reactor (112), the said support tube(114) being provided internally with a cartridge (116) containing a ball(118), the cartridge (116) having, around an inlet hole (121) for aprocessed fluid, a seat (122) for housing the said ball (118), andhaving slots (120) for the outflow of the said processed fluid,characterized in that the said cartridge (116) is fitted removably inthe said support tube (114).
 2. Non-return device (110) according toclaim 1, characterized in that at least one longitudinal aperture (124)is formed in the said support tube (114).
 3. Non-return device (110)according to claim 2, characterized in that the said at least onelongitudinal aperture (124) is a milled cut formed along the axis of thesaid support tube (114).
 4. Non-return device (110) according to claim3, characterized in that the said milled cut is created from an upperedge of the said support tube (114).
 5. Non-return device (110)according to claim 2, characterized in that a taper washer (126) isprovided for fixing the said cartridge (116) to the said support tube(114).
 6. Non-return device (110) according to claim 1, characterized inthat the said cartridge (116) is cylindrical.
 7. Non-return device (110)according to claim 1, characterized in that the said slots (120) areformed laterally in the said cartridge (116) and in that apertures inthe said support tube (114) correspond to the said slots (120). 8.Non-return device (110) according to claim 1, characterized in that thesaid seat (122) is provided in the lower part of the said cartridge(116).
 9. Non-return device (110) according to claim 1, characterized inthat the said support tube (114) is welded on to a portion of the saidreactor (112), in a vertical position.
 10. Non-return device (110)according to claim 1, characterized in that the said support tube (114)is fixed mechanically to a portion of the said reactor (112). 11.Non-return device (110) according to claim 2, characterized in that thesaid at least one longitudinal aperture (124) is formed in an area inwhich the said cartridge (116) is housed.
 12. Non-return device (110)according to claim 1, characterized in that the said seat (122) issuitably shaped to form a seal in conjunction with the said ball (118).